Conventional connections of a telephone switchboard are shown in FIG. 1˜FIG. 9.
Referring to FIG. 1, a telephone switchboard 1 (with telephone number 02-27712171) of Taipei Technology University has 38 outside connections, 1000 internal extensions (such as extensions 2178, 2104, 3178 . . . . ) and an auto-attendant 2.
A user uses extension 2178 for dialing to a mobile phone 0935-125356 through telephone switchboard 1 and Chung-Hwa Communication network 3, as shown in FIG. 2.
The subscriber of the mobile phone 0935-125356 does not accept the phone call, therefore a message “A call from 0227712171 was not accepted” is left in the mobile phone, as shown in FIG. 3.
Referring to FIG. 4, later on the subscriber of the mobile phone 0935-125356 notices the message “A call from 0227712171 was not accepted”, so he calls back the telephone number 0227712171 to the telephone switchboard 1 of Taipei Technology University through Chung-Hwa Communication network 3.
Referring to FIG. 5, the telephone switchboard 1 connects the call from the mobile phone 0935-125356 to the auto-attendant 2, and then the auto-attendant 2 sends out a voice response “This is Taipei Technology University, please dial the extension number” as shown in FIG. 6.
If the subscriber of the mobile phone 0935-125356 knows that it was the calling from extension 2178, he will of course dial the number 2178, as shown in FIG. 7.
Referring to FIG. 8, the auto-attendant 2 connects for the subscriber of the mobile phone 0935-125356 to the extension 2178 through the telephone switchboard 1. When the user of the extension 2178 picks up the phone call, the auto-attendant 2 will then drop out itself, and let the subscriber of the mobile phone 0935-125356 and the user of the extension 2178 communicate, as shown in FIG. 9.
But if the subscriber of the mobile phone 0935-125356 does not know who called him, he cannot dial a extension number after the voice response of the auto-attendant 2, even if he can ask for the assistance of an operator, he cannot ask the operator to connect which extension.
The above described condition happens frequently in modern life, especially in a big company, government or university that has thousands of extension.
U.S. Pat. No. 6,208,723 disclosed telecommunications systems and methods for automatically ringing a subscribers telephone once the subscriber's line becomes idle, and specifically to allowing an attendant to implement a recall feature for a third party when that party's line is busy, but this is not the solution to the above-described disadvantage.